The peptide adrenomedullin (ADM) was described for the first time in 1993 (Kitamura, K., et al., “Adrenomedullin: A Novel Hypotensive Peptide Isolated From Human Pheochromocytoma”, Biochemical and Biophysical Research Communications, Vol. 192 (2), pp. 553-560 (1993)) as a novel hypotensive peptide comprising 52 amino acids, which had been isolated from a human pheochromocytome; 21 SEQ ID NO: In the same year, cDNA coding for a precursor peptide comprising 185 amino acids and the complete amino acid sequence of this precursor peptide were also described. The precursor peptide, which comprises, inter alia, a signal sequence of 21 amino acids at the N-terminus, is referred to as “preproadrenomedullin” (pre-proADM). In the present description, all amino acid positions specified usually relate to the pre-proADM which comprises the 185 amino acids. The peptide adrenomedullin (ADM) is a peptide which comprises 52 amino acids (SEQ ID NO: 21) and which comprises the amino acids 95 to 146 of pre-proADM, from which it is formed by proteolytic cleavage. To date, substantially only a few fragments of the peptide fragments formed in the cleavage of the pre-proADM have been more exactly characterized, in particular the physiologically active peptides adrenomedullin (ADM) and “PAMP”, a peptide comprising 20 amino acids (22-41) which follows the 21 amino acids of the signal peptide in pre-proADM. The discovery and characterization of ADM in 1993 triggered intensive research activity, the results of which have been summarized in various review articles, in the context of the present description, reference being made in particular to the articles to be found in an issue of “Peptides” devoted to ADM in particular (Editorial, Takahashi, K., “Adrenomedullin: from a pheochromocytoma to the eyes”, Peptides, Vol. 22, p. 1691 (2001)) and (Eto, T., “A review of the biological properties and clinical implications of adrenomedullin and proadrenomedullin N-terminal 20 peptide (PAMP), hypotensive and vasodilating peptides”, Peptides, Vol. 22, pp. 1693-1711 (2001)). A further review is (Hinson, et al., “Adrenomedullin, a Multifunctional Regulatory Peptide”, Endocrine Reviews, Vol. 21(2), pp. 138-167 (2000)). In the scientific investigations to date, it has been found, inter alia, that ADM may be regarded as a polyfunctional regulatory peptide. It is released into the circulation in an inactive form extended by glycine (Kitamura, K., et al., “The intermediate form of glycine-extended adrenomedullin is the major circulating molecular form in human plasma”, Biochem. Biophys. Res. Commun., Vol. 244(2), pp. 551-555 (1998). Abstract Only). There is also a binding protein (Pio, R., et al., “Complement Factor H is a Serum-binding Protein for adrenomedullin, and the Resulting Complex Modulates the Bioactivities of Both Partners”, The Journal of Biological Chemistry, Vol. 276(15), pp. 12292-12300 (2001)) which is specific for ADM and probably likewise modulates the effect of ADM. Those physiological effects of ADM as well as of PAMP which are of primary importance in the investigations to date were the effects influencing blood pressure.
Hence, ADM is an effective vasodilator, and thus it is possible to associate the hypotensive effect with the particular peptide segments in the C-terminal part of ADM. It has furthermore been found that the above-mentioned further physiologically active peptide PAMP formed from pre-proADM likewise exhibits a hypotensive effect, even if it appears to have an action mechanism differing from that of ADM (cf. in addition to the abovementioned review articles (Eto, T., “A review of the biological properties and clinical implications of adrenomedullin and proadrenomedullin N-terminal 20 peptide (PAMP), hypotensive and vasodilating peptides”, Peptides, Vol. 22, pp. 1693-1711 (2001)) and (Hinson, et al., “Adrenomedullin, a Multifunctional Regulatory Peptide”, Endocrine Reviews, Vol. 21(2), pp. 138-167 (2000)) also (Kuwasako, K., et al., “Purification and characterization of PAMP-12 (PAMP-20) in porcine adrenal medulla as a major endogenous biologically active peptide”, FEBS Lett, Vol. 414(1), pp. 105-110 (1997). Abstract only), (Kuwasaki, K., et al., “Increased plasma proadrenomedullin N-terminal 20 peptide in patients with essential hypertension”, Ann. Clin. Biochem., Vol. 36 (Pt. 5), pp. 622-628 (1999). Abstract only) or (Tsuruda, T., et al., “Secretion of proadrenomedullin N-terminal 20 peptide from cultured neonatal rat cardiac cells”, Life Sci., Vol. 69(2), pp. 239-245 (2001). Abstract only) and EP-A2 0 622 458). It has furthermore been found that the concentrations of ADM which can be measured in the circulation and other biological liquids are, in a number of pathological states, significantly above the concentrations to be found in healthy control persons. Thus, the ADM level in patients with congestive heart failure, myocardial infarction, kidney diseases, hypertensive disorders, Diabetes mellitus, in the acute phase of shock and in sepsis and septic shock are significantly increased, although to different extents. The PAMP concentrations are also increased in some of said pathological states, but the plasma levels are lower relative to ADM ((Eto, T., “A review of the biological properties and clinical implications of adrenomedullin and proadrenomedullin N-terminal 20 peptide (PAMP), hypotensive and vasodilating peptides”, Peptides, Vol. 22, pp. 1693-1711 (2001)); page 1702). It is furthermore known that unusually high concentrations of ADM are to be observed in sepsis, and the highest concentrations in septic shock (cf. (Eto, T., “A review of the biological properties and clinical implications of adrenomedullin and proadrenomedullin N-terminal 20 peptide (PAMP), hypotensive and vasodilating peptides”, Peptides, Vol. 22, pp. 1693-1711 (2001)) and (Hirata, et al., “Increased Circulating Adrenomedullin, a Novel Vasodilatory Peptide, in Sepsis”, Journal of Clinical Endocrinology and Metabolism, Vol. 81(4), pp. 1449-1453 (1996)), (Ehlenz, K., et al., “High levels of circulating adrenomedullin in severe illness: Correlation with C-reactive protein and evidence against the adrenal medulla as site of origin”, Exp Clin Endocrinol Diabetes, Vol. 105, pp. 156-162 (1997)), (Tomoda, Y., et al., “Regulation of adrenomedullin secretion from cultured cells”, Peptides, Vol. 22, pp. 1783-1794 (2001)), (Ueda, S., et al., “Increased Plasma Levels of Adrenomedullin in Patients with Systemic Inflammatory Response Syndrome”, Am. J. Respir. Crit. Care Med., Vol. 160, pp. 132-136 (1999)) and (Wang, P., “Adrenomedullin and cardiovascular responses in sepsis”, Peptides, Vol. 22, pp. 1835-1840 (2001)).
Known in the art is further a method for identifying adrenomedullin immunoreactivity in biological liquids for diagnostic purposes and, in particular within the scope of sepsis diagnosis, cardiac diagnosis and cancer diagnosis. According to the invention, the midregional partial peptide of the proadrenomedullin, which contains amino acids (45-92) of the entire preproadrenomedullin, is measured, in particular, with an immunoassay which works with at least one labeled antibody that specifically recognizes a sequence of the mid-proADM (WO2004/090546).
WO-A1 2004/097423 describes the use of an antibody against adrenomedullin for diagnosis, prognosis, and treatment of cardiovascular disorders. Treatment of diseases by blocking the ADM receptor are also described in the art, (e.g. WO-A1 2006/027147, PCT/EP2005/012844) said diseases may be sepsis, septic shock, cardiovascular diseases, infections, dermatological diseases, endocrinological diseases, metabolic diseases, gastroenterological diseases, cancer, inflammation, hematological diseases, respiratory diseases, muscle skeleton diseases, neurological diseases, urological diseases.
It is reported for the early phase of sepsis that ADM improves heart function and the blood supply in liver, spleen, kidney and small intestine. ADM-neutralizing antibodies neutralize the before mentioned effects during the early phase of sepsis (Wang, P., “Adrenomedullin and cardiovascular responses in sepsis”, Peptides, Vol. 22, pp. 1835-1840 (2001).
In the later phase of sepsis, the hypodynamical phase of sepsis, ADM constitutes a risk factor that is strongly associated with the mortality of patients in septic shock. (Schütz et al., “Circulating Precursor levels of endothelin-1 and adrenomedullin, two endothelium-derived, counteracting substances, in sepsis”, Endothelium, 14:345-351, (2007)). Methods for the diagnosis and treatment of critically ill patients, e.g. in the very late phases of sepsis, and the use of endothelin and endothelin agonists with vasoconstrictor activity for the preparation of medicaments for the treatment of critically ill patients have been described in WO-A1 2007/062676. It is further described in WO-A1 2007/062676 to use, in place of endothelin and/or endothelin agonists, or in combination therewith, adrenomedullin antagonists, i.e. molecules which prevent or attenuate the vasodilating action of adrenomedulin, e.g. by blocking its relevant receptors, or substances preventing the binding of adrenomedullin to its receptor (e.g. specific binders as e.g. antibodies binding to adrenomedullin and blocking its receptor bindings sites; “immunological neutralization”). Such use, or combined use, including a subsequent or preceding separate use, has been described in certain cases to be desirable for example to improve the therapeutic success, or to avoid undesirable physiological stress or side effects. Thus, it is reported that neutralizing ADM antibodies may be used for the treatment of sepsis in the late stage of sepsis.
Administration of ADM in combination with ADM-binding-Protein-1 is described for treatment of sepsis and septic shock in the art. It is assumed that treatment of septic animals with ADM and ADM-binding-Protein-1 prevents transition to the late phase of sepsis. It has to be noted that in a living organism ADM binding protein (complement factor H) is present in the circulation of said organism in high concentrations (Pio et al.: Identification, characterization, and physiological actions of factor H as an Adrenomedullin binding Protein present in Human Plasma; Microscopy Res. and Technique, 55:23-27 (2002) and Martinez et al.; Mapping of the Adrenomedullin-Binding domains in Human Complement factor H; Hypertens Res Vol. 26, Suppl (2003), S56-59).
In accordance with the invention the ADM-binding-protein-1 may also be referred to as ADM-binding-protein-1 (complement factor H).
Administration of ADM may thus be beneficial in an early stage of a disease like e.g. sepsis but may be detrimental in a later stage of sepsis. The opposite may be the case with the administration of anti-ADM antibodies. Further, dosing may be critical when applying ADM or anti-ADM antibodies.
For other diseases blocking of ADM may be beneficial to a certain extent. However, it might also be detrimental if ADM is totally neutralized as a certain amount of ADM may be required for several physiological functions. In many reports it was emphasized that the administration of ADM may be beneficial in certain diseases. In contrast thereto in other reports ADM was reported as being life threatening when administered in certain conditions. The disadvantage of the prior art may be overcome with the anti-ADM antibodies or anti-ADM antibody fragments or anti-ADM non-Ig scaffolds provided by the present invention.